XCON: Messages from Blocked Domain Bypass Global Filtering If Certain Special Characters Are in Address (312604)

SYMPTOMS

When you configure global message filtering to block messages that originate from a specific domain, some messages from that domain may bypass filtering. The messages that bypass filtering have certain special characters in the P2 From header address.

The following circumstances allow a message to bypass Exchange 2000 Server filtering:

• Using quotation marks (") anywhere in the address itself (the quotation marks correctly appear around the sender's display name)

  Example:
  
  From: "DisplayName" <a"b@abc.com>

• Using a square bracket or brackets ([ ]) anywhere in the address

  Examples:
  
  From: "DisplayName" <a[b@abc.com>
  
  From: "DisplayName" <[ab]@abc.com>

• Using a period (.) after the @ symbol

  Example:
  
  From: "DisplayName" <ab@.abc.com>

• Omitting either or both of the necessary angle brackets (< >)

  Example:
  
  From: "DisplayName" ab@abc.com>

• Using more than one "at" symbol (@)

  Example:
  
  From: "DisplayName" <ab@@abc.com>